Workers from former Eastern Bloc nations will become eligible to claim hundreds of pounds in jobseeker’s allowance, council tax help and housing benefits.

Migrants will be able to receive the benefits because restrictions on eligibility – introduced through a scheme introduced by the European Union seven years ago - are due to be abolished in May.

Under EU law all restrictions on citizens of new member states must end after a seven-year “transitional” period.

Ministers conceded last night they are powerless to prevent the changes because Britain needed to maintain “our national and international obligations”. The three benefits combined could be worth up to £250 a week, per person, The Times reported.

The disclosures will lead to concerns that a fresh wave of migrants will embark on "benefit tourism" placing an even greater strain on public finances.

Officials at the Department of Work and Pensions have pledged to be vigilant against fraud and promised to crack down on abusers.

Under the changes, nationals from the eight states will be able to access the three benefits as long as they can prove they have worked in Britain, sought more work and intend to live here.

It also means that tough rules introduced by other EU countries will also be scrapped. At the time the EU expanded only Britain, the Irish Republic and Sweden opened up their jobs market.

It means that countries such as Germany and Austria will be opening their doors to workers for the first time from May.

The scheme was introduced by Labour ministers in 2004 amid concerns that migrants from poor nations would arrive in Britain en masse.

After it was introduced following eight former Soviet bloc states joining the EU it led to “the largest single wave of foreign in-movement ever experienced by the UK”, according to the Office for National Statistics (ONS).

Migrants were barred from receiving jobseeker’s allowance, housing and council tax benefit unless they had worked here continuously for twelve months. But very few qualified mainly due to their work was seasonal.

Official figures show that since 2005 hundreds of thousands of migrants have registered to work, reaching a peak of 224,195 in 2006.

That number fell after that but rose at the end of last year as Britain emerged from recession.

Damian Green, the Immigration Minister, said the Coalition would impose “transition controls2 on all new EU member states in future.

“We’re in the process of delivering major reform to bring immigration down to tens of thousands with the introduction of a new limit on economic migrants from outside the EU,” he said.

A DWP spokesman added: “We have to remain in line with our national and international obligations.

“However, it is absolutely necessary to protect the taxpayer and the benefit system from possible abuse. This is our No 1 priority.”